Brief description Einstein's General Theory of relativity has passed all tests so far with flying colors. But most of the tests near the solar system where the effects of gravity are quite weak. Dense objects like neutron stars or black holes curve the space-time in their vicinity to much higher magnitudes. If these objects are in binary systems, such curvature affects the orbital motion. J1141-6545 is a distinctive laboratory where one object of the binary system is a neutron star and the other is a white-dwarf star. Observing this system sheds light on how the uneven space-time curvature of the system affects our understanding of gravity.